Rotary switch device



Jan. 5, 1954 Filed Aug. 30, 1950 B. s. BENSON 2,665,343 ROTARY SWITCHDEVICE 2 Sheets-Sheet 1 IN V EN T 0R. fife x420 j 55,4450

Jan. 5, 1954 s, BENSON 2,665,343

ROTARY SWITCH DEVICE Filed Aug. 50, 1950 2 Sheets-Sheet 2 3/ :LINVENTOR.

- Arrows 5Y- Patented Jan. 5, 1954 ROTARY SWITOH DEVICE Bernard S.Benson, Malibu, Calif., assignor to Douglas, Aircraft Company, Inc.,Santa Monica,

Calif.

Application August 30, 1950, Serial No. 182,363

6 Claims.

This invention relates to converting devices and more particularly tosuch a device for converting continuously varying values into discretedigital form,

The device of the present invention, in the broadest aspects thereof,comprises means for translating variable values indicative of theposition of a movable part into discontinuous discrete form, Thecontinuously varying values are, in the illustrated embodiment of theinvention, translated into rotational movement of a shaft which carriesa contact element movable over a plurality of contact members fixed in aspaced apart relationship;

Each contact member forms a part of a normally open electric circuit andthese normally open circuits are seriately energized as the contactelement relatively moves into engagement with themembers in accordancewith the rotational movement indicative of the continuously varyingvalue. The seriate energization of the circuits thus form discrete ordiscontinuous registrations of the progression of the movable part. Eachcircuit may include an electro-responsive element capable of furnishingthe signal or indication desired, depending upon the field of use of thedevice. Where a decimal system of measurement is desired, the membersare decadel, that is, ten in number although it will be obvious that thesegments could be other than ten in number.

"To eliminate the possibility of a contact element coming to restintermediate an adjacent pair of members to thus produce an impositivesignal, means are provided for rapidly moving the contact elementrelative to the members as the contact element moves towarddisengagement with an engaged member to bring about substantiallyinstantaneous movement of the contact element into engagement with thenext adjacent member. Thus, even though the motion of the part producingrelative movement between the contact element and the members over whichthe contact element relatively moves may cease, the device of thepresent invention is incapable of producing an impositive signal for thecontact element is prevented from coming to rest intermediate anadjacent pair of members, Furthermore, the substantially instantaneousmovement of the contact element from one member to the next adjacentmember reduces to a minimum the time lag in the transit of the elementfrom one member to the next.

The means used to produce thesubstantially iiitaiitaneoiis movement, inthe illustrated embodiment of the present invention, comprises magneticmeans carried by the contact element. Arranged adjacent each contactmember is a mass of ferromagnetic material which, through magneticattraction, tends to hold the contact element in engagement with amember. The contact element, in all embodiments of the inventionillustrated, is mounted for independent movement relative to the rotatedshaft but is held by resilient means in a normal position relative tosaid member.

The contact element thus is held in engagement with a segment eventhough the rotated shaft continues to rotate as the part is moved. Oncethe force exerted by the resilient means is greater than the magneticforces tending to hold the contact element in engagement with themember, the contact element is quickly swept into engagement with thenext adjacent member. The magnetic means of the contact element againholds the latter in engagement with this member until the rotated shafthas again moved in its cycle to a position in which the magnetic forcesare less than those created by the resilient means, whereupon theelement is again quickly swept into engagement with the next member.

Other features and advantages of the present invention will behereinafter apparent from the following description, particularly whentaken in connection with the accompanying drawing, in which Figure 1 isa perspective view of the device of the present invention with portionsbroken away to more clearly illustrate certain structural details;

Figure 2 is a schematic showing of the electrical circuits thereof;

7 Figure 3 is a section taken along line 3-3 of Figure 1; and

Figure 4 is aperspective View of a portion of a modified form of thepresent invention.

The device of the present invention, referring now to the drawing andmore particularly to Figure 1, comprises a suitable casing-like memberID including a wall element il having a circular opening formed thereinpresenting a cylindrical wall surface I2. The wall element ll carries abracket i3 including a suitable bearing member [4 for supporting a shaftI 5 for rotation about an axis coincident with the axis of saidcyiindrical wall surface [2. The shaft [5, by some suitable means, isdrivingly connected to a continuously moving element such as, forexample, a rotatably driven shaft, the rotations of which are to beregistered or indicated. It should be made clear dinal extension of thearm I8.

here that the device of the present invention is not limited tomeasuring or recording the revolutions of a rotatably driven member for,by conventional rack and pinion means, straight line motion of a movingmember can be easily translated into rotational movement, which movementin turn can be used to rotatably drive the shaft I5.

To simplify the disclosure of the device of the present invention,however, the device will be described herein as one for translating thecontinuously varying values represented by a rotating shaft I6,referring now to Figure 3, and coupled to the outer end of the shaft I5by some suitable coupling device, indicated at H, into discrete,discontinuous form.

Referring again to Figure 1, it will be seen that the shaft I-5 adjacentthe inner end thereof carries a radially extending arm I8 which will bemoved about the opening as the shaft is rotatably driven. The arm I8terminates at its free end in a longitudinally extending slot receivinga lug I9 projecting from the end face of a member 2I. A pin 2Ia passedthrough aligned openings formed in the bifurcations of the arm I8 andthe lug I9 pivotally mounts the member 2I to the outer end of the armI6. The member 2I, in the embodiment of the invention shown in Figure l,is formed of magnetic material suitably magnetized to form a permanentmagnet. The magnet may be of bar form in which the poles thereof arelocated at opposite ends thereof, although preferably the member 2 I isformed as a U-shaped or horseshoe magnet in which both poles are locatedat the outer or free end of the member. The slot or passage between thelegs of the mag-.

net may be filled with some suitable non-magnetic material, as indicatedat 22.

Fixed to the one face of the arm I8 is an elongate leaf spring 23, whichspring extends longitudinally of the arm i8 beyond the outer end'thereof and this projecting end of the spring is permanently fixed tothe magnet 2 I The spring is such that it normally holds the magnet 2!in a position in which the same forms a longituever, will permit themember 2I to pivotally move in either direction about the axis formed bythe pin 2Ia so that the magnet may move independently of the arm I8.

A resilient contact element 24 is fixed to the one face of the magnet 2|and extends outwardly beyond the pole faces thereof. This contactelement will be moved in a circular path as the shaft is rotatedsubstantially coincident with that portion of the front face of the Wallelement II which forms the defining edge of the circular opening.Embedded within the material forming the wall element II are a pluralityof segments 25, ten in number, and spaced apart an equal distancecircumferentially of the cylindrical wall surface I2. The one face ofeach segment is substantially flush with the cylindrical wall surface I2while the adjacent side face of each element is substantially flush withthe front surface, that is, that surface of the wall element I I overwhich the projecting portion of the contact element 25 moves.

The outer end face of the magnet is preferably given a cylindricalcontour substantially conforming to the cylindrical wall surface I2.Thus, as the magnet rotatably moves about the opening, the pole facesthereof are just slightly spaced from those faces of the segments 25which are substantially flush with the wall surface I2.

Fixed by any means desired to that side face The spring, howof eachsegment which is substantially flush with the front surface of the wallelement I I is a contact member 26. It will be seen that these contactmembers are seriately engaged by the resilient contact element 24 as theshaft I5 is rotatably driven from the shaft I6.

Each contact member 26 includes aterminal element 21 which extendsrearwardly of the wall element II. A conductor 28 is led from eachterminal element 21 to an electro-responsive element 29, here shown as asmall incandescent lamp or the like. The lamps 29, electricallyconnected to the contact members 26 are disposed in openings linearlyarranged on the wall element II, as best shown in Figure 1. Each lamp29, referring now to Figure 2, is connected to a source of current,indicated at 3I, through a common lead or conductor 32.

The arm I8 is grounded, as indicated at 33, and engagement of thecontact element 24 with each contact member 26 completes the circuit ofthe lamp 29 electrically connected to the engaged contact member. Itshould be understood now that the energization of the lamps 29, as thecontact element 24 seriately engages the contact members 26, willindicate or register the position of the element 2e relative to thecircumferentially arranged contact members 26. As the contact element 24is carried by the arm I8 which is moved in accordance with thecontinuously varying value represented by the rotating shaft I6, theenergization of the lamps 29 will consequently indicate or register indiscrete, discontinuous form the quantum of this varying value.

To simplify the signal or indication made by an energized lamp and topresent the signal in digital form, the wall element I I may carry smalltranslucent discs 34 closing the openings in which the lamps 29 aredisposed. These linearly arranged discs 34 will carry indicia in theform of the digits, as clearly shown in Figure 1. The contact members 26are so connected by the leads 28 to the lamps 29 that energization ofany lamp will indicate, in tenths, a partial revolution of the shaft I6.This is done merely serially connecting the segments to the lampsarranged adjacent the discs bearing digits. Thus, if the shaft isrotated nine-tenths of a revolution, the contact element 24. will beengaged with the 9th segment electrically connected to the lamp 29arranged adjacent the discs 34 bearing the digit pivotally mounted tothe outer end of th arm I8 and can pivotally move against the action ofthe spring 23 relative to the arm I8 as the latter sweeps onward pastthe segment 25 substantially aligned with the magnet 2I. Once the armlahas moved to some position intermediate this segment and the nextadjacent segment in which the resilient forces created by the now flexedspring 23 are greater than the holding force created by the magneticfield, the magnet 2| will be quickly swept toward the next adjacentsegment. This movement of the magnet carries the contact element 2 1quickly from the engaged contact 'spectsto the contact element 24-.element 43 is adaptedto be successively engaged with contact members 44carriedby segments45 5 member 26 toward engagement with the nextadjacent contact member 26.

As the contact element 24 is swept toward engagement with the nextadjacent contact member 26, the magnetic attraction between the magnet2i and the segment 25, to which the next adjacent contact member isfixed, will augment the forces moving the contact element and, ineffect, draw the magnet into substantial alignment therewith. As themagnet moves into a position substantially aligned with this segment,the magnetic forces again will hold the contact member 24 in engagementwith the contact member until the arm [8 is again moved to a position inwhich the holding force created by the magnetic field is less than theforce created by the again flexed spring 23. At this time, as should nowbe clearly understood, the magnet and th contact member 34. will besubstantially instantaneously again pivotally moved by the spring 23relative to the arm Hi to carry the contact element 24 into engagementwith the next adjacent contact member 26. Thus, as the contact element24 is successively moved substantially instantaneously by the flexedspring 23 from one contact member to the next, there is no danger of thedevice supplying an impositive signal for there is little likelihood,even upon cessation of movement of the shaft l6, that the. contactelement 24 would comev to rest in a position intermediate any adjacentpair of con tact members 26. The successive engagement of the contactelement with the contact members 26 resulting in successive energizationof the lamps 29 will, as should now be understood, resultin a positiveregistration at discrete intervals of the varying value indicative ofthe angular displacement of the shaft l6. In the embodiment of th deviceof the present invention shown in Figure 4, an arm 35, similar infunction to the arm [8, is connected to the one end of a shaft 36substantially identical to the shaft I5, for limited arcuate movementrelative to the shaft 36. In the now preferred form of mounting the arm35 to the shaft 36-, the latter is fitted with a key 31 longitudinallyextending at the inner end of the shaft. The one end of the arm 35; isformed with a cylindrical passageway for receiving the inner end of theshaft 36 and opening into this cylindrical passageway is a coextensivekeyway 38, the opposed walls of which diverge outwardly from thecylindrical passageway. The keyway 38- is substantially larger than thekey 31 to perm-it the arm 35 to arcuately move a limited distancerelative to the axisof theshaft 36.

Any. means desired may be used to hold the arm 35 against movementlongitudinally of the shaft 36 and one such means may comprise anelongate slot 39 formed in the-endface of the arm 35 for-passing athreaded stud or bolt 4| received a tapped opening formed in the innerend of the shaft 36. The slot 39 should be of such a length that thestud 4| will move from one-end to the other as the key 31 moves froma'position engaging one of the diverging; walls of the keyway 38 to aposition in which itis engaging the opposed diverging wall. The arm 35,in the embodiment of the invention. now being described, carries at itsouter end a, permanent horseshoe magnet 42 to which is fixed a contactelement 43 identical in all re- The contact formedof some ferromagneticmateial carried about a cylindrical Wall surface concentric with theshaft 36. The contact members 44, like coritact members 26, areelectrically connected to some electro-responsve means, such as lampssimilar to the lamps 29 of the earlier described embodiment of theinvention. Such lamps would be successively energized as the contactelement 43 successively moves into engagement with the contact members44 to register in discrete form the progression of the shaft 36.

In this embodiment of the invention, a pair of resilient elements fixedto the arm, such as leaf springs 46 projecting into the keyway andterminating adjacent the opposed diverging walls thereof, tend to holdthe arm 35 in a normal position relative to the shaft 36 but yetallowthe arm 35 to arcuately move relative to the shaft 36. In theoperation of the embodiment of the invention now being described, theattraction between the magnet 42 and a segment 45 will tend to hold thearm 35 against movement and substantially aligned with a segment 45 asthe shaft 36 continues to rotate until such time as the resilient forcecreated by the compression of one of the springs 46 is greater than theholding force of the magnet.

When the resilient force is greater than the holding force of themagnet, the arm 35 and consequently the contact element 43 will bequickly swept arcuately to a position in which the contact element 43 isengaged with the next adjacent contact member 44. In this movement ofthe arm 35, the particular means used to mount the arm 35 to the shaft36 will permit the arm 35 to accelerate and move relative to the shaft36 to a position in which the arm 35 is actually ahead of the shaft 36.As the shaft 36 continues to rotate, the key 31 will move intoengagement with one or the other of the springs 46, depending upon thedirection of rotation of the shaft 36 to again initiate compression ofone of the springs 46. This is so, for the holding force of the magnet42 will tend to hold the arm 35 against movement with the shaft 36. Atthe point where the force created by the compressed spring is, againgreater than the holding force of the magnet, the arm 35 will again bequickly swept forwardly to again bring the contact element 43. intoengagement with the next adjacent contact member 44.

It; will thus be seen that, in both embodiments of the invention hereinillustrated, means are provided for translating variable valuesindicative of the position of a movable part into discontinuous,discrete form. Thereis no possibility of the contact element coming torest intermediate adjacent pairs of contact members for in all embodiments illustrated, means are provided for rapidly moving the contactelement relative to the contact members as the contact element movesvtoward disengagement with an engaged contact member to bring aboutsubstantially instantaneous movement of the contact element intoengagement with the next adjacent contact member. I

Although the now preferred embodiments of the present invention havebeen shown and described herein, it is to be understood that theinvention is not to be limited thereto, for it is susceptible to changesin form and detail within the scope of the appended claims, For example,

electro-magnets could obviously be substituted for the permanent magnetshown.

I claim:

1. A device, of the type described, comprising: av master memberadaptedto be rotatably driven from a moving part; magnetic means; meansfor mounting said magnetic means to said master member for limitedmovement with respect to said master member and movable therewith in acircular path of travel as said master member is rotatably driven;resilient means normally resisting retrograde and progressive movementof said magnetic means in said path relative to said master member asthe latter is rotatably driven, said magnetic means including a contactelement movable therewith; and a plurality of equally spaced apartferro-magnetic segments, including contact portions, carried by a wallsurface concentrically circumscribing said master member and arrangedsubstantially coincident with the path of travel of said contactelement; the magnetic forces created by movement of said magnetic meansinto a position juxtaposed with one of said segments holding saidcontact element in engagement with the contact portion of saidjuxtaposed segment as said master member continues to rotate until saidmagnetic forces are less than the movement resisting forces of saidresilient means, whereupon said resilient means substantiallyinstantaneously moves said magnetic means into juxtaposed relationshipwith the next adjacent segment to thus move said contact elementsubstantially instantaneously into engagement with the contact portionof said next adjacent segment.

2. A device of the type described, comprising: a shaft adapted to berotatably driven from a moving part; an arm radially extending from saidshaft; a magnet carried at the outer end of said arm; resilient meansnormally holding said magnet in a predetermined position relative tosaid shaft whereby the magnet normally moves in a circular path oftravel with said shaft as the latter is rotated, said resilient meansnormally resisting retrograde and progressive movement of said magnet insaid path relative to said shaft as the latter is rotated; a contactelement carried by said magnet and movable therewith in a circular pathof travel as the shaft is rotatably driven; a plurality of equallyspaced apart ferro-magnetic segments carried by a wall surfaceconcentrically circumscribing said shaft and substantially coincidentwith the path of travel of said contact element; and a contact membercarried by each segment; the magnetic forces created by movement of saidmagnet into position juxtaposed with one of said segments holding saidcontact element in engagement with the contact member carried by saidjuxtaposed segment as said shaft continues to rotate until said magneticforces are less than the movement resisting forces of said resilientmeans whereupon said resilient means substantially instantaneously movessaid magnet to said normal position relative to said shaft to thus movesaid contact element substantially instantaneously out of engagementwith the contact member carried by said juxtaposed segment. 7

3. A device of the type described, comprising: a master member adaptedto be rotatably driven from a moving part; a permanent magnet; means formounting said magnet to said master member for limited movement withrespect to said master member and movable therewith in a circular pathof travel as said master member is rotatably driven; resilient meansnormally resisting retrograde and progressive movement of said magneticmeans in said path relative to said master member as the latter isrotatably driven, said magnetic means including a contact elementmovable therewith; a plurality of equally spaced apart ferro-magneticsegments, including contact portions, carried by a wall surfaceconcentrically circumscribing said master member and arrangedsubstantially coincident with the path of travel of at least one poleface of said permanent magnet; the magnetic forces created by movementof said permanent magnet into a position in which at least one pole facethereof is juxtaposed with one of said segments holding said contactelement in engagement with the contact portion of said juxtaposedsegment as said master member continues to rotate until said magneticforces are less than the movement resisting forces of said resilientmeans, whereupon said resilient means substantially instantaneouslymoves said permanent magnet into a position in which at least the onepole face thereof is in juxtaposed relationship with the next adjacentsegment to thus move said contact element substantially instantaneouslyinto engagement with the contact portion of said next adjacent segment.

4. A device of the type described, comprising: a shaft adapted to berotatably driven from a moving part; an arm radially extending from saidshaft; a magnet pivotally carried at the outer end of said arm;resilient means normally holding said magnet in a predetermined positionrelative to said arm whereby the magnet normally moves in a circularpath of travel with said arm as the shaft is rotated, said resilientmeans normally resisting pivotal movement of said magnet relative tosaid arm as the shaft is rotated; a contact element carried by saidmagnet and movable therewith in a circular path of travel as the shaftis rotatably driven; a plurality of equally spaced apart ferro-magneticsegments carried by a wall surface concentrically circumscribing saidshaft and substantially coincident with the path of travel of saidcontact element; a contact member carried by each segment; the magneticforces created by movement of said magnet into position juxtaposed withone of said segments holding said contact element in engagement with thecontact member carried by said juxtaposed segment as said magnetpivotally moves relative to said arm as said shaft continues to rotateuntil said magnetic forces are less than the movement resisting forcesof said resilient means whereupon said resilient means substantiallyinstantaneously moves said magnet to said normal position relative tosaid arm to thus move said contact substantially instantaneously out ofengagement with the contact member carried by said juxtaposed segment.

5. A device of the type described comprising: a shaft adapted to berotatably driven from a moving part; means presenting an innercylindrical wall surface concentrically circumscribing said shaft; aplurality of equally spaced apart ferromagnetic segments carried by saidmeans and each having a face substantially flush with said wall surface;a contact member carried by each segment; an arm; means for mountingsaid arm to said shaft for limited pivotal movement relative thereto; amagnet carried at the outer end of said arm, at least one pole face ofsaid magnet moving in a circular path, as said shaft is rotated,substantially coincident with said cylindrical wall surface; a contactelement carried by said magnet; and resilient means normally holdingsaid arm in a preselected position relative to said shaft and resistingpivotal movement of said arm relative to said shaft as the latter isrotatably driven to thereby cause said contact element to seriately moveinto engagement with said contact members, the magnetic forces createdby movement of said magnet into a position juxtaposed with one of saidsegments arresting movement of said arm to hold said contact element inengagement with the contact member carried by said juxtaposed segment assaid shaft continues to rotate until said magnetic forces are less thanthe movement resisting forces of said resilient means, whereupon saidresilient means substantially instantaneously pivotally moves said armrelative to said shaft to thereby move said magnet into juxtaposedrelationship with the next adjacent segment to thus move said contactelement substantially instantaneously into engagement with the contactmember carried by said next adjacent segment.

6. A device of the type described comprising: a shaft adapted to berotatably driven from a moving part; means presenting an innercylindrical wall surface concentrically circumscribing said shaft; aplurality of equally spaced apart ferromagnetic segments carried by saidwall surface; a contact member carried by each segment; an arm radiallyextending from said shaft; a permanent magnet carried at the outer endof said arm, at least one pole face of said magnet moving in a circularpath, as said shaft is rotated, substantially coincident with saidcylindrical wall surface; a contact element carried by said magnet andseriately movable into engagement with said members as said shaft isrotatably driven; and resilient means normally holding said contactelement in a preselected spatial position relative to said shaft andyieldably resisting displacement of said contact element from saidposition, the magnetic forces created by movement of said magnet into aposition juxtaposed with one of said segments holding said contactelement in engagement with the contact member carried by said juxtaposedsegment as said shaft continues to move to thereby displace said contactelement from said preselected position relative to said shaft until saidmagnetic forces are less than the displacement resisting forces of saidresilient means, whereupon said resilient means substantiallyinstantaneously moves said magnet relative to said shaft into juxtaposedrelationship with the next adjacent segment to thus move said contactelement substantially instantaneously into engagement with the contactmember carried by said next adjacent segment.

BERNARD S. BENSON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 823,164 Eble June 12, 1906 1,135,040 Missbach Apr. 13, 19151,420,026 Eckre June 20, 1922 1,446,552 Dunn Feb. 27, 1923 1,530,936Greenwood Mar. 24, 1925

